Granular coated web and method of making same



March 1936. R. c. BENNER ET AL A 2,035,521

GRANULAR COATED WEB AND METHOD OF MAKING SAME Filed Oct. 26, 1932 2Sheets-Sheet l O IF 13 O i J INVENTORS RAYMOND G, BENNER QOVHE L. MELTONy HENRY 9 K\RGHNER ATTORNEY GRANULAR COATED WEB AND METHOD OF MAKINGSAME Filed Oct. 26, 19:52 2 Sheets-Sheet 2 INVENTORS RAYMOND QBENNERROMHi L MELTON BY HENRY P KlRCHNER ATTORNEY Patented Mar. 3,1, 1936UNITED STATES PATENT OFFICE GRANULAR COATED wan AND METHOD F MAKINGYSAMEApplication October 26, 1932, Serial No. 639,598

4 Claims.

This invention relates to the manufacture of granular coated webs, suchas abrasive paper and cloth and various nonabrasive granular coatedProducts.

Granular coated webs, as they have been made in the past, have hadsurface coatings of granular material without particular order inposition or orientation. In other words, the granules have not beenarranged on'the web but have been haphazardly deposited thereon. Thegranular material was fed by gravity'onto the adhesive coating and, as aresult, the particles assumed positions flat on the web. With sucharrangement, or rather lack of arrangement, it has not been possible tosecure the-maximum efficiency of abrasion because a great many of theparticles were so positioned that their sharper edges were not inpositions whereby they could engage the Work.

20 v More recently it has been proposed to make abrasive coated webs byarranging the particles on the web in such fashion that the major axesof a substantial proportion, of the particles are normal to the surfaceof the web. ,An abrasive faster than the previously known abrasive websbecause a large proportion of the particles of the formerly known typeof web were embedded fiatwise in the adhesive and consequently were oflimited use in abrading, whereas particles arranged in such a, mannerthat their major axes are normal to the surface of the web are also sopositioned that they presentsharp cutting points or edges to thematerial undergoing abrasion;

We have found that superior coated webs can be produced by sopositioning the granular material that a substantial proportion ofgrains are individually oriented and inclined with their longerdimensions at an oblique angle with respect to the surface of the web.Such an inclination of the grain causes each particle to dig into thesurface of the substance being abraded, when the abrasive articleismoved with respect to the work, or vice versa, in somewhat the samegeneral manner as the inclined teeth of a saw dig in and turn up a chip.This tendency of the abrasive particles to dig into the work surfacecauses faster abrading action, yet the abrasive particles are sopositioned that-they are not readily torn from the web as is the casewhen they are arranged normal to the surface of the web.

One method by which coated webs having the abrasive granules arranged onthe surface at an oblique angle to the surface of the web can be madeconsists essentially in so positioning the coated web of this naturehas'a tendency to cut web after it has received a coating of adhesiveand a coating of granular particles arranged with their major axesnormal to the surface of the web, that the granular particles hangdownward while the web itself is inclined at an oblique angle 5,

with respect to the vertical. The adhesive, being freshly applied andtherefore not hardened or set, permits gravitational attraction to causethe particles to rotate about their attached ends until they hangdownward in a vertical direction. 10 By causing the coated web to remainin this position until the adhesive has acquired at least a partial set,whereby the granular particles become fixed in position, the particlescan be arranged on the web so that substantially all of i5 them are atan oblique angle with respect to the surface of the web.

Arrangement of the particles normal to the surface of the web can beaccomplished by blowing them with a blast of high velocity,low volumeair from a screen upwardly to a web having its adhesive coated sidedownward. The particles, as they move upwardly with the assistance ofthe air blast, orient themselves so thatthey strike. the adhesive coatedweb in endwise fashion and therefore project substantially normally fromthe adhesive coated web; Our copending application, Serial No. 647,241filed December 14, 1932, discloses and-claims this method of projectingthe particles upwardly by means of, a blast of high velocity, low volumeair.

Another way in which the particles can be caused to be arranged at anoblique angle with respect to the surface of the web consists in movinga web with a fresh coating of adhesive and granular particles arrangedsubstantially normal to the surface thereof into contact with a rollerrod so positioned that it gently tips the particles over to the desiredangle with respect to the surface of the web. Inasmuch as this step 40must be carried out while the adhesive still is soft and unset, it isdesirable to position the web after the particles have been'tipped overin such a manner that the particles hang down vertically while the webis at anoblique angle with respect to the vertical, and to hold it insuch a position until the adhesive has acquired at least a fitmnesssuflicient to-prevent further movement of the particles with respect tothe surface of the web.

While the previously mentioned methods of positioning the granules onthe surface of the web have involved as a first step 'thedeposition ofthe grains normal to the surface of the web, the same resu t can .beaccomplished by depositing the grains on the adhesive coated web at theangle desired without first orienting them normal to the web. This canbe done by so positioning the means for holding the adhesive coated weband the means for projecting the granular material that the particlesare deposited on the adhesive coated web at the desired angle. A betterunderstanding of this phase of our invention can be had by reference tothe accompanying drawings, in which:

Fig. 1 is an enlarged side view of the usual granular coated article,

Fig. 2 is an enlarged side view of a granular coated article made inaccordance with this invention,

Fig. 3 is a diagrammatic side elevation of a sanding device utilizing anabrasive belt made in accordance with the present invention,

Fig. 4 is an enlarged sectional view of a portion of Fig. 3,

Fig. 5 is a diagrammatic side elevation of one form of apparatus, and

' Fig. 6 is a section along. the line II-II of Fig. 5.

the usual method of coating abrasive webs and that of articles madeaccording to our invention, is illustrated in Figs. 1 and 2,respectively. The grains 2 in the previously known articles, as shown inFig. 1, do not have their sharpest surfaces projecting at an angle withrespect to the plane of the web, and therefore, are not free for theabrading action. On the other hand, as shown by the side view of anabrasive coated web made in accordance with our invention, asillustrated in Figs. 2 and 4, the grains 4 are oriented and inclined sothat their sharpest or needle-like points form the abrading surface, andwhen moved in the direction indicated by the arrow 6, dig into the worksurface and therefore out faster than the previously known abrasivepaper.

Abrasive coated webs made in accordance with our invention have beenfound to possess excellent abrading characteristics. When the granularparticles are uniformly inclined in the direction of movement of theweb, they readily dig into the surface of the work piece and thusincrease the cutting rate of the abrasive.

Abrasive coated webs of widely different characteristics can be securedby making articles having different degrees of angularity between thegranular particles and the backing. Those coated webs with the grains ata small angle of inclination tend to penetrate the Work surface. to agreater degree than those with a larger angularity. It usually isadvisable to make the angle of inclination of the granular particlesfrom about to about 75 with respect to the surface of the web.

The cutting action of an abrasive coated web. made in accordance withthe present invention. is illustrated in Figs. 3 and 4. Referring toFig. 3, an abrasive belt 8 having an inclined granular coating iscarried by the driving roll or pulley l0 and the idler roll II. Thisabrasive belt is held in contact with the work piece I2 by the member13, which also provides a means for applying pressure indicated by thearrow F, to the back of said belt. The work piece I2 is supported on atable I4, which is vertically adjustable to compensate for varyingthicknesses of the work piece.

When the abrasive belt 8 is moved in the direction-indicated by thearrow 6, the points of the granular particles 4 engage the surface ofthe work piece l2 at an angle and more readily penetrate the surfacethereof. As illustrated by the enlarged view in Fig. 4, the inclinedgranular particles 4 cut or dig into the surface somewhat in the fashionof a farmer's plow making a furrow in the surface of the earth, sincethe long granular particles are relatively sharp at the points.

A further advantage lies in the fact that the twisting or turningmovement of the particles about their bases, which is produced by theresistance of the work surface to abrasion, is greatly reduced becausethe particles penetrate more easily. This is a marked improvement overother types of abrasive web, such as those recently proposed, in whichthe granular particles are oriented perpendicularly to the plane of thework surface.

Since abrasive webs with the grains arranged at an oblique angle, asdescribed above, possess different cutting properties, depending uponthe relative direction of motion between the abrasive coated web and thework surface, we have found that certain desirable results can beobtained by causing relative motion in a direction opposite to that bywhich the particles dig into the work. When the motion is in a directionopposite to that illustrated in Figs. 3 and 4, the inclined granularparticles make an angle less than 90 with respect to the unabradedsurface, and polish the work surface rather than rapidly abrade it. Lessstock is removed from the material being abraded by this method, but theresulting surface is smoother and approaches that of a polished surface.Thus, by reversing the relative direction of movement of the abrasivebelt, illustrated in Fig. 3, the same rapid cutting abrasive belt can beused for a finishing operation in which it is desired to remove a verysmall amount of material and produce a polish or high finish.

Referring to Fig. 5, which illustrates apparatus for producing coatedwebs embodying our in vention, there are shown means A for holding anddispensing a roll l6 of the web P which may be of paper, cloth or thelike, and which, for

purposes of brevity, will herein be referred to as the web; means B forapplying adhesive to one side of the web P; means C for applyinggranular material to the adhesive side of the web P at a predeterminedangle thereto; means D for caus- &

ing a preliminary set of the adhesive; and means E for drawing the webthrough the coating apparatus and into a drying chamber.

The means A for holding and dispensing the web P comprises, as shown inthe drawings, a

frame I! that supports the roll l6 of web P; an idler roll l8 forguiding the web; printing rolls l9 and for marking the web with anydesired legend or identification; and an idler roll 2| for guiding theweb.

The adhesive applying means B comprises, as shown in the drawings, idlerrolls 23 and 24 for guiding the web; a roll 26 positioned to dip into apan 21 of adhesive; a roll 25 for maintaining contact between the web Pand the roll 26; a drum 28 and an adhesive distributing brush 29positioned above the said drum 28; and an idler roll 30 for guiding theweb as it is brought from the adhesive distributing brush.

Means C for applying granular material to the web P comprises, as shownin the drawings, an idler roll 32 which is both horizontally andvertically adjustable, as shown, for guiding and positioning the web; agrain hopper 33 with an adjustable gate 34 and a, roll 35 for dispensingthe (ill the web P. The combination of the grain projecting means andweb positioning meansis representative of apparatus herein referred toas orienting means-.

The means D for causing the adhesive to acquire a preliminary setcomprises, as shown in the drawings, an adjustable idler roll and asource 4| for supplying a large volume of air at a low velocity to theadhesive and granular coated side of the web P.

The means E for drawing the web, P from the coating apparatus into thedrying chamber comprises, as shown in the drawings; one or more suctiondrums 43 and 44; an idler roll a rack 41 for supporting the web P; andan endless conveyor 46 for transporting loops of the web P tothe rack41. u

" In the normal operation of the apparatus illustrated in Fig.5, a rollof the uncoated, web P, such as paper or cloth,- is rotatably mounted onthe frame I1 and the web is threaded over the roll I8 and between theprinting rolls l9 and 20,

thence in contact with the idler rolls 2|, 23 and 24 to the pressureroll 25 and the adhesive roll 26. The adhesive roll dips into liquidadhesive contained in the adhesive tank 21, and on the upward-movementof travel of the roll 26, a layer of adhesive is applied to .the web. Ii

The adhesively coated web P passes betweenth brush drum '28 and avibrating brush 29 which evenly distributes the adhesiveand smoothes outany ridges. It is then guided by the idler roll 30 and adjustable roll32 past the grain projecting apparatus 31. t

Granular particles are distributed from the grain hopper 33 onto thegrain projecting means 31, shown in section in Fig. 6, and upontraveling down this chute, the elongated particles are oriented by thechannels so that their longer axes are parallel to the direction ofmotion. After leaving the end of the grainprojecting means 31, theparticles strike the adhesive coated surface of the web P and becomeembedded therein.

Immediately after being coated with granular material, the web P is madeto turn upward past the roll 32, over the fan blower 4|, and toward roll40, the angularity' of the web being so adjusted by the positioning ofthe roll 40 that the granular particles are substantially vertical. Theweb is maintained in this position until the adhesive has acquired atleast a partial set by the action of the air from the blower 4|,whereupon it may be moved in any direction desired without disturbingthe orientation of the granular particles. By positioning the web at anangle whereby the grains hang downward, the force of gravity not onlyoperates to preserve orientation, but to promote orientation by causingthe particles to turn to a vertical position.

Orienting means, one form of which is illustrated in the drawings,consist essentially of a combination of means whereby the grains and theweb are brought toegther in such fashion I and has no axis susceptibleto orientation. "Such grain, of course, can not be orientedadvantageously, but it does contribute to fast cutting characteristicsof the web because it is projected onto the web at an oblique angle andtherefore becomes positioned on the web in much the same manner as thosegrains that are of the elongated type. r

, Abrasive granular-material as received usually consists ofa mixture ofelongated and blocky grains, the proportions of which will varydepending upon the composition of the grain and also on the kind ofapparatus used in reducing the crude material to smaller sizes. Whileour apparatus will, orient the elongated particles that occur in theusual granular material, andwill position the blocky type in somewhatthe same way, we usually find it desirable to separate the two types,selecting grains, containing at least a 7 Whonabrasive coated websembodying our 7 invention are moved in contact-with the materialundergoing abrasion in such manner, that the particles dig into thematerial, or in other words, so that the angle between theunabradedsurface of the. material and the major axes oi the granularmaterial is greater than 90, the abrading process can be carried on witha greater efliciency than has been known heretofore. Each particle actsin a manner similar to the blade of a carpenter's plane and thusdisengages from the mass of the material being abraded, a portion morelike a shaving than the usual particle which resembles and iscalled;dust. The plane-like action of each grain on a web embodying ourvinvention increases the eiiiciency of the abrading operation because thearrangement of the grains and the direction that the grains are movedwith respect to the material being abraded permit ing a fibre or a groupof fibres from the main body of the wood, and since the arrangement ofthe grains and the direction that they move with respect to the materialbeing abraded permits each abrasive grain to penetrate more deeply intothe wood with the same expenditure of energy, it becomes obvious that agroup of fibres can be removed from the main body with no greaterexpenditure of energy as is required to remove a fibre or a portion of afibre by the use of the abrasive coated webs known heretofore. Thus, theamount of work required to remove a unit volume of material is less whendone with an abrasive coated web embodying our invention in themannerdescribed herein.

usual dragging action inherent in the use of the previously knownabrasive coated webs. Another advantage that contributes tothe greaterefficiency in the use of abrasive coated webs embodying our inventionresults from the fact that the abrasive particles are not subjected tothe same tearing out action that is inherent in the use of the abrasivecoated webs heretofore known. Since theparticles on the surface of a webembodying our invention penetrate the work and remove a portion thereofwith less expenditure of energy, it is obvious that they will remainattached to the web for a longer period of time than will the grains onthe coated abrasive webs known heretofore.

When the abrasive particles are arranged on the web so that their majoraxes are at an oblique angle with respect to the, surface of the web,they abrade with less chattering than when the particles are arrangedwith their major axes normalto the web. This is brought about by thefact that the oblique particles penetrate the work more readily, whereasthe particles arranged perpendicular to the web have more of a tendencyto drag across the surface and as they drag they intermittentlypenetrate the work. This intermittent penetration has the tendency toset up vibrations or chattering, which causes the particles to becomeloosened, and therefore easily removed from the web.

Other advantages will be apparent from the foregoing disclosure to thoseskilled in the art and while specific embodiments have been used toillustrate our invention, it is to be understood that the invention isnot limited to those embodiments but is defined by the appended claims.

We claim:

1. In the manufacture of granular coated webs, the method comprisingpositioning elongated granular particles upon an adhesive coated web,with the major axes of the particles at an angle of less than 180 withrespect to the surface of the web, and supporting the freshly coated webat an oblique angle with respect to the horizontal and with the coatedside down until the adhesive has acquired at least a preliminary set.

2. In the manufacture of granular coated webs, the method comprisingpositioning elongated granular particles upon an adhesive coated-web,with the major axes of the particles at an angle of less than 180' withrespect to the surface of the web, orienting substantially all of theparticles with their axes parallel and at an oblique angle with respectto the surface of the web, and supporting the freshly coated web at suchan angle with respect to the horizontal that the oriented particles hangvertically downward until the adhesive has acquired at least apreliminary set.

3. As a new article of manufacture, a granular coated web in which asubstantial proportion of the granular particles are uniformly orientedwith their longer dimensions inclined at an oblique angle with respectto the plane of the web.

4. As a new article of manufacture, a granular coated web, a substantialproportion of the;

granular particles of which are of an elongated character, saidelongated particles being so oriented that their longest dimensions areinclined at an oblique angle with respect to the surface of the web.

RAYMOND C. BENNER. ROMIE L. MELTON. HENRY P. KIRCHNER.

